Agent skill

Comfyui Frontend Extensions

by artokun in artokun/comfyui-mcp

Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles.

MITAuto-check passedAI & LLM Engineering

Install Comfyui Frontend Extensions

skills CLI
$ npx skills add artokun/comfyui-mcp --skill comfyui-frontend-extensions -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install artokun/comfyui-mcp comfyui-frontend-extensions --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/artokun/comfyui-mcp.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugin/skills/comfyui-frontend-extensions .claude/skills/comfyui-frontend-extensions && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
comfyui-frontend-extensions
GitHub stars
803
Token cost
~5.4k tokens
SKILL.md length
1,441 words
Files
2 (incl. references)
Skills in repo
42
Repo updated
First seen
Licence
MIT

At a glance

Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles.

  • Works in 11 steps: Calling lifecycle hooks after await.… → Reaching for window.app or app.*. v2 has… → Patching nodeType.prototype. Replaced by… → …
  • Editing ComfyUI web-UI extension code (custom node JS
  • SKILL.md covers Mental model, Registration entry points, defineNode — the primary entry… and defineExtension — app…, plus 9 more sections
  • Reaches github.com

What it does

Comfyui Frontend Extensions is an agent skill from artokun/comfyui-mcp. Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles. Use when writing or editing ComfyUI web-UI extension code (custom node JS, sidebar panels, widgets).

Its SKILL.md is about 5.4k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/migrate-v1-to-v2.md`).

It sits in AI & LLM Engineering, covering Diffusion and image models. It works with ComfyUI and Node.js. The repository describes itself as: Local-first, agent-native control plane for ComfyUI — MCP server + sidebar agent that generates images, video & audio, authors and runs workflows, and edits your live graph in… The licence is MIT.

When your agent uses it

  • Editing ComfyUI web-UI extension code (custom node JS
  • Tasks that involve Diffusion and image models

Example prompts

  • “/comfyui-frontend-extensions”

Requirements

  • Python 3

Workflow steps

11 steps, taken from the first numbered list in SKILL.md.

  1. Calling lifecycle hooks after await. onNodeMounted / onMounted / onUnmounted rely on implicit scope context and must be called…
  2. Reaching for window.app or app.*. v2 has no window.app dependency at module-eval time. Import everything from @comfyorg/extension-api.
  3. Patching nodeType.prototype. Replaced by defineNode + node.on(...). Prototype patching does not interoperate with the v2 handle model.
  4. Mutating reads. node.getInputs(), widget.options, and Point/Size tuples are frozen/Readonly; assignment raises TS errors. Use the setter…
  5. Assigning widget.value / widget.callback / widget.serializeValue. Use setValue(), on('valueChange'), and on('beforeSerialize')…
  6. Trying to disable widget serialization. There is no serialize: false and no skip() in v2. If a widget should not contribute to the…
  7. Creating widgets at runtime. node.addWidget(...) / node.addDOMWidget(...) are removed. Declare widgets in the Python INPUT_TYPES; render…
  8. Enumerating widgets from a node. node.getWidget(name) / node.getWidgets() were removed (nodes cannot reference widgets). Use a…
  9. Using node-level beforeSerialize. Deprecated (ADR-0010). Store extension state in a widget and use widget-level beforeSerialize.
  10. Forgetting to dispose. Long-lived subscriptions made outside a setup() context, and every defineX handle, leak unless you call the…
  11. Relying on deferred Phase A exports. Position/size/title/mode getters and slot/connection events are not yet exported. Don't write code…

What it can do on your machine

Read from SKILL.md and the folder at commit 6ad6fc0. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Hosts in commands or code, which the agent is likely to contact:

    • github.com

    Also links to:

    • npmjs.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Comfyui Frontend Extensions loads about 5.4k tokens when it runs, and up to ~8.3k if it reads all its reference files. Until then it costs about 80 tokens; SKILL.md has 1,441 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~80
When it runs · the whole SKILL.md, loaded when a task matches
~5.4k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~8.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from artokun/comfyui-mcp at commit 6ad6fc0, republished under its MIT licence (© artokun). 1,441 words, ~5,353 tokens.

Download SKILL.mdSave it as .claude/skills/comfyui-frontend-extensions/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
comfyui-frontend-extensions
description
Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles. Use when writing or editing ComfyUI web-UI extension code (custom node JS, sidebar panels, widgets).

ComfyUI v2 Frontend Extension API

The v2 extension API is the published npm package @comfyorg/extension-api. It replaces the legacy app.registerExtension() / nodeType.prototype monkey-patching model with a typed, tree-shakeable, import-based API.

If you are converting an existing v1 extension, read references/migrate-v1-to-v2.md for a pattern-by-pattern mapping.

Mental model

v1 (legacy)v2 (@comfyorg/extension-api)
One giant app.registerExtension({...}) callOne defineX per concern, each independently disposable
window.app / app.* globalsDirect import from the package; no window.app at module-eval time
nodeType.prototype.onExecuted = ... patchingnode.on('executed', fn) on a NodeHandle
Mutate widget.value, assign widget.callbackwidget.setValue(v) / widget.on('valueChange', fn)
api.addEventListener('execution_start', fn)execution.on('start', fn) (typed namespaces)
Manual removeEventListener bookkeepingEvery subscription returns Unsubscribe; every defineX returns DisposableHandle

Core principles baked into the API:

  • Import, don't reach for globals. import { defineNode } from '@comfyorg/extension-api'. No window.app dependency at module evaluation time.
  • Read via getters, write via command-dispatch setters. getValue() reads; setValue() dispatches an undo-able, serializable command. Read-only invariants (set at construction) are readonly accessors (node.type, widget.name).
  • Observe via typed on(...) subscriptions. Each returns an Unsubscribe cleanup function. No Vue refs/signals are ever exposed; Vue reactivity is the internal engine only.
  • Everything is disposable. Every defineX returns a DisposableHandle with an idempotent, synchronous dispose().

Registration entry points

All imported from @comfyorg/extension-api:

FunctionPurposeReturns
defineNode(opts)Primary entry — react to node lifecycle (replaces prototype patching)NodeExtensionOptions
defineExtension(opts)App-scoped lifecycle (init/setup) + shell UI hostExtensionOptions
defineWidget(opts)Register a custom widget type (DOM via mount)WidgetExtensionOptions
defineSidebarTab(opts)Add a left-sidebar tab (Vue or custom)DisposableHandle
defineBottomPanelTab(opts)Add a bottom-panel tabDisposableHandle
defineToolbarButton(opts)Add an action-bar buttonDisposableHandle
defineCommand(opts)Register an invokable commandDisposableHandle
defineHotkey(opts)Bind a key combo to a command idDisposableHandle
defineSetting(opts)Add a settings-menu entryDisposableHandle
defineAboutBadge(opts)Add a badge to the About pageDisposableHandle

Imperative carve-outs (fire-and-forget, not defineX, no handle): toast, notify.

A single extension file typically exports a default defineExtension/defineNode result and calls the shell-UI defineX functions inside setup() or at module scope. They queue safely before the app boots.

defineNode — the primary entry point

Reacts to node lifecycle. nodeCreated fires once per node instance (typed in, pasted, duplicated, or loaded without an existing workflow). loadedGraphNode fires once when a node is restored from a saved workflow (widget values already populated). Exactly one of them fires per node entity, never both.

ts
import { defineNode, onNodeMounted, onNodeRemoved } from '@comfyorg/extension-api'

export default defineNode({
  name: 'my-org.executed-logger',
  // Filter to specific comfyClass names. Omit to receive every node type.
  nodeTypes: ['KSampler', 'KSamplerAdvanced'],

  // MUST be synchronous. Runs inside a Vue EffectScope; everything registered
  // here (subscriptions, onNodeMounted) auto-disposes when the node is removed.
  nodeCreated(node) {
    // Read-only invariants
    console.log(node.type, node.comfyClass, node.id)

    // Subscribe to backend execution completion (replaces onExecuted patching)
    node.on('executed', (e) => {
      console.log('output:', e.output) // Record<string, unknown>
    })

    // Lifecycle hooks — call SYNCHRONOUSLY (never after an await)
    onNodeMounted(() => {
      // Node fully mounted; DOM/canvas ready.
    })
    onNodeRemoved(() => {
      // Cleanup: abort fetches, close sockets. Does NOT fire on subgraph promotion.
    })
  },

  loadedGraphNode(node) {
    // Node restored from a saved workflow; widget values are already set.
  }
})
NodeHandle surface (Phase A)
MemberKindNotes
id: stringreadonlyOpaque token. Compare with node.equals(other), never by slicing.
equals(other)methodCanonical identity comparison.
type: stringreadonlyLiteGraph node type.
comfyClass: stringreadonlyBackend class name.
getProperty<T>(key) / getProperties() / setProperty(key, v)methodsPer-instance props (migration shim — prefer widget values).
getInputs() / getOutputs()methodsReadonlyArray<Readonly<SlotInfo>> — frozen views.
on('executed', fn)methodExecution complete → NodeExecutedEvent { output }.
on('removed', fn)methodNode deleted (not subgraph promotion).
on('configured', fn)methodLoaded from saved workflow (after widget values restored).
on('beforeSerialize', fn)methodDeprecated — use widget-level beforeSerialize (ADR-0010).

Position/size/title/mode getters and slot/connection events are deferred in Phase A. Do not rely on getPosition, setSize, getMode, on('connected').

Nodes cannot enumerate or reference their widgets (node.getWidget(name) was removed). Use defineWidget and the mount context's ctx.widget handle.

defineExtension — app lifecycle + shell UI

Use for app-wide setup and to host shell-UI registrations. setup() runs at the early registration point; use the imported onMounted hook for work that needs the app fully initialized.

ts
import {
  defineExtension,
  onMounted,
  onUnmounted,
  execution,
  toast
} from '@comfyorg/extension-api'

export default defineExtension({
  name: 'my-org.my-extension',
  setup() {
    // Register late-lifecycle work via onMounted (called synchronously here).
    onMounted(() => {
      const off = execution.on('start', () => {
        toast.show({ severity: 'info', summary: 'Run started' })
      })
      onUnmounted(off) // tidy teardown
    })
  }
})

A note on the setup() signature. The source-of-truth API uses implicit-context hooks: import onMounted/onNodeMounted/etc. and call them synchronously inside setup() (mirrors Vue's Composition API). An early package draft showed a setup(ctx) { ctx.onNodeMounted(...) } context-argument style; prefer the imported-hook form above, which is what the current API exports.

Context-scoped lifecycle hooks are imported and called synchronously inside defineExtension's setup(): onBeforeMount, onMounted, onUnmounted, onActivated, onDeactivated. defineSidebarTab/defineBottomPanelTab take no setup field; adding one is a type error. onActivated/onDeactivated fire when the surrounding tab or panel is shown or hidden.

defineWidget — custom widget types with DOM

Widgets are declared in the Python node's INPUT_TYPES, never created at runtime (node.addWidget is forbidden). defineWidget registers a type and the DOM mount hook the runtime invokes against a host <div> it owns. mount is optional; omit it for value-only widgets that render through the native renderer.

ts
import { defineWidget, type WidgetCleanup } from '@comfyorg/extension-api'

export default defineWidget({
  name: 'my-org.color-picker',
  type: 'COLOR_PICKER', // referenced from Python INPUT_TYPES

  // The SOLE DOM seam. Capture host + constructed DOM via closure — there is
  // no widget.element accessor.
  mount(host, ctx): WidgetCleanup {
    const input = document.createElement('input')
    input.type = 'color'
    input.value = String(ctx.widget.getValue() ?? '#000000')
    input.addEventListener('input', () => ctx.widget.setValue(input.value))
    host.appendChild(input)

    // ctx.widget / ctx.node are the only legal handles here.
    ctx.widget.on('valueChange', (e) => {
      input.value = String(e.newValue ?? '#000000')
    })

    // Optional cleanup — fires once on widget destruction (NOT on host remount).
    return () => input.remove()
  }
})

WidgetMountContext also exposes onUnmount(fn), onBeforeRemount(fn), and onAfterRemount(fn => ...) for host-move scenarios (graph↔app mode, subgraph promotion). The mount body is not re-invoked across a remount; only the remount hooks fire.

WidgetHandle surface
MemberKindNotes
id / equals(other)readonly / methodOpaque identity.
name / widgetType / labelreadonlySet from INPUT_TYPES schema.
getValue<T>() / setValue(v)methodssetValue dispatches an undo-able command.
optionsreadonlyReadonly<WidgetOptions> snapshot. Writes raise TS errors.
getOption<K>(key) / setOption(key, v)methodsPer-instance overrides (e.g. min/max/step).
setHeight(px)methodResize the reserved host height (DOM widgets).
on('valueChange', fn)methodWidgetValueChangeEvent { oldValue, newValue }.
on('optionChange', fn)methodWidgetOptionChangeEvent { key, oldValue, newValue }.
on('beforeSerialize', fn)methodOnly async-allowed event. e.value + e.setSerializedValue(v).
on('beforeQueue', fn)methodPre-queue validation. Call e.reject(msg) to cancel.
ts
// Serialization override (the SOLE serialization interface in v2):
widget.on('beforeSerialize', (e) => {
  e.setSerializedValue(processDynamicPrompt(widget.getValue()))
})

// Async serialization (e.g. capture a webcam frame before queueing):
widget.on('beforeSerialize', async (e) => {
  e.setSerializedValue(await captureFrame())
})

// Pre-queue validation (replaces app.queuePrompt monkey-patching):
widget.on('beforeQueue', (e) => {
  if (!widget.getValue()) e.reject('Prompt text is required before queueing.')
})

Typed event namespaces

Four module-level singletons replace api.addEventListener('...'). Each on() returns an Unsubscribe. Subscriptions made inside a setup() body auto-dispose on unmount; subscriptions made elsewhere are the caller's responsibility.

NamespaceEvents (canonical)Wire mapping
executionstart, end, error, interrupted, cached, executing, progress, previewexecution_<evt>
graphchanged, …graph:<evt>
serverstatus, logs, reconnected, feature_flags, assets, + custom-node eventsraw event name
workbenchnotification, …workbench:<evt>
ts
import { execution, server } from '@comfyorg/extension-api'

const off = execution.on('progress', (e) => console.log('progress', e))
// Custom-node events ride the `server` namespace with arbitrary names:
server.on('my-org.my-node.update', (e) => console.log(e))
// later:
off()

Payloads default to unknown today. Narrow them with TS module augmentation:

ts
declare module '@comfyorg/extension-api' {
  interface ExecutionEventPayloads {
    start: { promptId: string }
    progress: { value: number; max: number }
  }
  interface ServerEventPayloads {
    'my-org.my-node.update': { nodeId: string; text: string }
  }
}

The augmentable interfaces are GraphEventPayloads, ExecutionEventPayloads, ServerEventPayloads, and WorkbenchEventPayloads.

Show full SKILL.md (587 more words)Show less

Shell UI registrations

Each returns a DisposableHandle. Safe to call at module scope (they queue until the app boots) or inside setup().

ts
import {
  defineCommand,
  defineHotkey,
  defineToolbarButton,
  defineSetting,
  defineAboutBadge
} from '@comfyorg/extension-api'

// Command — id, function, optional label/icon/tooltip.
const cmd = defineCommand({
  id: 'my-org.do-the-thing',
  label: 'Do The Thing',
  function: () => { /* ... */ }
})

// Hotkey — binds a key combo to an already-registered command id.
// `mod` = cmd on macOS, ctrl elsewhere.
defineHotkey({ keys: 'mod+shift+k', commandId: 'my-org.do-the-thing' })

// Action-bar button — id (for dispose), icon, onClick.
defineToolbarButton({
  id: 'my-org.help',
  icon: 'pi-question-circle',
  tooltip: 'Get help',
  onClick: () => openHelp()
})

// Setting — widen the id when not augmenting the Settings keymap.
defineSetting({
  id: 'my-org.enabled' as never,
  name: 'Enable my extension',
  type: 'boolean',
  defaultValue: false
})

// About-page badge.
defineAboutBadge({
  label: 'GitHub',
  url: 'https://github.com/me/my-ext',
  icon: 'pi-github'
})

// Tear down any registration:
cmd.dispose() // idempotent + synchronous

CommandDefinition fields: id (required), function: (metadata?) => void | Promise<void> (required), optional label / icon / tooltip (each string | (() => string)), menubarLabel, versionAdded.

defineSidebarTab — embedded panels (e.g. a chat panel)

A sidebar tab hosts a rich embedded UI such as a chat panel. It comes in two flavors: type: 'vue' (mount a Vue component) or type: 'custom' (imperative render(container) / destroy()). Both share the base fields id, title, optional icon, iconBadge, tooltip, label.

Vue component tab
ts
import { defineSidebarTab } from '@comfyorg/extension-api'
import ChatPanel from './ChatPanel.vue'

const chatTab = defineSidebarTab({
  id: 'my-org.chat',
  title: 'Chat',
  type: 'vue',
  icon: 'pi-comments',
  component: ChatPanel
})
// chatTab.dispose() removes the tab.
Custom (framework-free) chat panel

When you don't want a Vue dependency, use type: 'custom' and build the DOM yourself. render receives the container; destroy is your teardown.

ts
import {
  defineExtension,
  defineSidebarTab,
  execution,
  server,
  type Unsubscribe
} from '@comfyorg/extension-api'

export default defineExtension({
  name: 'my-org.chat-panel',
  setup() {
    const subscriptions: Unsubscribe[] = []

    defineSidebarTab({
      id: 'my-org.chat',
      title: 'Chat',
      type: 'custom',
      icon: 'pi-comments',

      render(container: HTMLElement) {
        const log = document.createElement('div')
        log.className = 'chat-log'

        const form = document.createElement('form')
        const input = document.createElement('input')
        input.placeholder = 'Ask something…'
        const send = document.createElement('button')
        send.type = 'submit'
        send.textContent = 'Send'
        form.append(input, send)

        const append = (who: string, text: string) => {
          const line = document.createElement('p')
          line.textContent = `${who}: ${text}`
          log.appendChild(line)
          log.scrollTop = log.scrollHeight
        }

        form.addEventListener('submit', (ev) => {
          ev.preventDefault()
          const text = input.value.trim()
          if (!text) return
          append('You', text)
          input.value = ''
          // Forward to a backend node/server event, stream the reply, etc.
        })

        container.append(log, form)

        // Stream backend replies via the server namespace (custom-node event).
        subscriptions.push(
          server.on('my-org.chat.reply', (e) => append('Assistant', String(e)))
        )
        // React to runs to show status in the panel.
        subscriptions.push(
          execution.on('start', () => append('System', 'Run started…'))
        )
      },

      destroy() {
        for (const off of subscriptions) off()
        subscriptions.length = 0
      }
    })
  }
})

defineBottomPanelTab has the same vue / custom shapes (base fields id, optional title/titleKey, optional targetPanel: 'terminal' | 'shortcuts').

Toasts

toast and notify are inline imperative (no defineX, no handle). Call from any setup() body or hook closure.

ts
import { toast } from '@comfyorg/extension-api'

toast.show({ severity: 'error', summary: 'Workflow failed', detail: err.message, life: 4000 })
toast.removeAll()

notify({ kind, message, detail, life }) is a deprecated 1:1 wrapper over toast.show. Prefer toast.show directly.

Node identity helpers

For referencing nodes across subgraph boundaries or execution runs, use the branded identity types rather than raw integer node IDs:

ts
import {
  createNodeLocatorId, parseNodeLocatorId, isNodeLocatorId,
  createNodeExecutionId, parseNodeExecutionId, isNodeExecutionId,
  type NodeLocatorId, type NodeExecutionId
} from '@comfyorg/extension-api'

const locator: NodeLocatorId = createNodeLocatorId(subgraphUuid, localNodeId)
// NodeExecutionId encodes a node's path through nested subgraphs as an array of node ids
// (joined with ':'). Pass the array, not positional args:
const execId: NodeExecutionId = createNodeExecutionId([localNodeId])

if (isNodeLocatorId(maybe)) {
  // parseNodeLocatorId returns { subgraphUuid: string | null; localNodeId: NodeId }
  const { subgraphUuid, localNodeId } = parseNodeLocatorId(maybe)
}

NodeLocatorId arrives from workflow JSON; NodeExecutionId arrives from websocket frames. You receive these from event payloads, which is why they're public (unlike the internal *EntityId brands, which are not exported).

Disposal contract

Every defineX returns DisposableHandle { dispose(): void }:

  • Idempotent. Calling dispose() again is a safe no-op.
  • Synchronous. Teardown happens synchronously inside dispose().
  • Independent. Disposing handle A does not affect B or C. Sequence calls explicitly when teardown order matters (e.g. drop a hotkey before its command).
  • Pre-mount safe. Disposing before the app boots removes the spec from the pending queue so it never mounts.
ts
const handles = [
  defineCommand({ id: 'my.cmd', function: () => {} }),
  defineHotkey({ keys: 'mod+k', commandId: 'my.cmd' }),
  defineSidebarTab({ id: 'my.tab', title: 'Tab', type: 'vue', component: MyTab })
]
// Full teardown:
for (const h of handles.reverse()) h.dispose()

Common mistakes

  1. Calling lifecycle hooks after await. onNodeMounted / onMounted / onUnmounted rely on implicit scope context and must be called synchronously inside the setup()/nodeCreated body. After an await the scope is gone: it throws in dev and is a silent no-op in prod. Kick off async work in the body, but register hooks first.
  2. Reaching for window.app or app.*. v2 has no window.app dependency at module-eval time. Import everything from @comfyorg/extension-api.
  3. Patching nodeType.prototype. Replaced by defineNode + node.on(...). Prototype patching does not interoperate with the v2 handle model.
  4. Mutating reads. node.getInputs(), widget.options, and Point/Size tuples are frozen/Readonly; assignment raises TS errors. Use the setter methods (widget.setOption, widget.setValue).
  5. Assigning widget.value / widget.callback / widget.serializeValue. Use setValue(), on('valueChange'), and on('beforeSerialize'). serializeValue is read-only in v2.
  6. Trying to disable widget serialization. There is no serialize: false and no skip() in v2. If a widget should not contribute to the payload, it should not be a widget. The only serialization interface is widget.on('beforeSerialize', fn) + e.setSerializedValue(v).
  7. Creating widgets at runtime. node.addWidget(...) / node.addDOMWidget(...) are removed. Declare widgets in the Python INPUT_TYPES; render custom DOM via defineWidget({ mount }).
  8. Enumerating widgets from a node. node.getWidget(name) / node.getWidgets() were removed (nodes cannot reference widgets). Use a defineWidget mount context's ctx.widget, or share state via the server event bus.
  9. Using node-level beforeSerialize. Deprecated (ADR-0010). Store extension state in a widget and use widget-level beforeSerialize.
  10. Forgetting to dispose. Long-lived subscriptions made outside a setup() context, and every defineX handle, leak unless you call the returned Unsubscribe / dispose(). Inside setup() they auto-dispose on unmount.
  11. Relying on deferred Phase A exports. Position/size/title/mode getters and slot/connection events are not yet exported. Don't write code against them.

Sources

© artokun, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in plugin/skills/comfyui-frontend-extensions of artokun/comfyui-mcp.

  • SKILL.md
  • references/migrate-v1-to-v2.md

Open the folder on GitHubat commit 6ad6fc0

Compare with similar skills

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  • Comfyui Skill Openclaw

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    Run registered ComfyUI workflows through the fast comfyui-skill CLI, and use the official local Comfy MCP for live template, node, model, validation, and orchestration capabilities.

    413 GitHub stars~2.7k tokensUpdated 1 mo ago
    AI & LLM EngineeringAuto-check passed
  • ComfyUI Custom Node Builder

    ConstantineB6/comfy-pilot

    Helps an agent write ComfyUI custom nodes in Python, including wrapping an existing script, mapping data types and handling image batches.

    230 GitHub stars~897 tokensUpdated 7 mo ago
    AI & LLM EngineeringAuto-check passed
  • Continuity Render

    roadmaus/ComfyUI-Continuity

    Render videos and pictures on a ComfyUI server that has the Continuity node pack (MiniMax H3, LTX 2.5, Krea 2, Ideogram 4, Qwen Image, Flux 2 Klein) with one command, the render.py bundled in this…

    133 GitHub stars~1.7k tokensUpdated 2 days ago
    AI & LLM EngineeringAuto-check passed
  • Add Comfyui Node

    Mooshieblob1/MooshieUI

    Adds a custom ComfyUI Python node to MooshieUI — Python class in mooshienodes.py, Rust required-class registration, and optional workflow template chain hookup.

    207 GitHub stars~936 tokensUpdated today
    AI & LLM EngineeringAuto-check passed
  • Edit Comfy Workflow

    peteromallet/VibeComfy

    Edit an existing VibeComfy or ComfyUI workflow, ready template, recipe, scratchpad, or target graph.

    150 GitHub stars~2.2k tokensUpdated 8 days ago
    AI & LLM EngineeringAuto-check passed
  • H3 Prompt Director

    dagthomas/comfyui_dagthomas

    Core craft for writing MiniMax H3 video prompts as the engine behind the APNext H3 nodes in ComfyUI - how to obey the node's directives (task type, duration, shot plan, camera, dialogue, wildness)…

    290 GitHub stars~1.9k tokensUpdated 1 mo ago
    AI & LLM EngineeringAuto-check passed

More from artokun/comfyui-mcp

All 42 skills in this repo
  • AI Toolkit Trainer

    artokun/comfyui-mcp

    Train custom LoRAs with ostris AI-Toolkit. An agent skill from artokun/comfyui-mcp.

    803 GitHub stars~2.7k tokensUpdated 4 days ago
    Auto-check passed
  • Anima Base

    artokun/comfyui-mcp

    Anime/illustration text-to-image (ANIMA 1.0, ~2B Cosmos DiT).

    803 GitHub stars~4k tokensUpdated 4 days ago
    Auto-check passed
  • Civitai

    artokun/comfyui-mcp

    Discover Civitai models with the BUILT-IN downloadmodel action:"searchcivitai" and install/generate them locally.

    803 GitHub stars~1.1k tokensUpdated 4 days ago
    Auto-check passed
  • Color Correction

    artokun/comfyui-mcp

    Diagnose and fix video/image color OBJECTIVELY with the getimage (action:"analyzecolor") tool (scopes/stats such as black/white points, contrast, saturation, clipping, cast) instead of eyeballing a…

    803 GitHub stars~2.4k tokensUpdated 4 days ago
    Auto-check passed
  • Comfyui Launch Flags

    artokun/comfyui-mcp

    Pick the right ComfyUI startup flags for VRAM, attention, caching, and speed.

    803 GitHub stars~3.1k tokensUpdated 4 days ago
    Auto-check passed
  • Installer Packs

    artokun/comfyui-mcp

    A skill your agent uses when installing a model family from an installer pack, or when building/deriving a new pack from an upstream installer or a workflow JSON.

    803 GitHub stars~952 tokensUpdated 4 days ago
    Auto-check passed

Works with

Questions about Comfyui Frontend Extensions

What does Comfyui Frontend Extensions do?

Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles. Comfyui Frontend Extensions is an agent skill from artokun/comfyui-mcp. Authoring ComfyUI v2 frontend extensions with @comfyorg/extension-api, covering defineNode/defineExtension/defineWidget, shell UI (sidebar tabs, commands, hotkeys), typed events, and handles.

When should I use Comfyui Frontend Extensions?

Comfyui Frontend Extensions fits situations like: editing ComfyUI web-UI extension code (custom node JS; tasks that involve Diffusion and image models.

How do I install Comfyui Frontend Extensions in Claude Code?

Run `npx skills add artokun/comfyui-mcp --skill comfyui-frontend-extensions -a claude-code`. Or copy the skill folder (plugin/skills/comfyui-frontend-extensions in artokun/comfyui-mcp) into .claude/skills/comfyui-frontend-extensions in your project. Claude Code loads it when a task matches its description.

How do I install Comfyui Frontend Extensions in Codex?

Run `npx skills add artokun/comfyui-mcp --skill comfyui-frontend-extensions -a codex`. Or copy the skill folder (plugin/skills/comfyui-frontend-extensions in artokun/comfyui-mcp) into .agents/skills/comfyui-frontend-extensions in your project. Codex loads it when a task matches its description.

Can I use Comfyui Frontend Extensions in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add artokun/comfyui-mcp --skill comfyui-frontend-extensions -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/comfyui-frontend-extensions, .gemini/skills/comfyui-frontend-extensions, .github/skills/comfyui-frontend-extensions and .opencode/skills/comfyui-frontend-extensions in your project.

What does Comfyui Frontend Extensions need to run?

SKILL.md names no scripts, command-line tools or credentials: Comfyui Frontend Extensions is instructions for the agent only. Our summary lists: Python 3.

Does Comfyui Frontend Extensions access the network?

SKILL.md names 2 domains. In commands or code: github.com; the agent is likely to contact it when it follows the instructions. As links in the text: npmjs.com. This is read from the text; nothing was executed.

Is Comfyui Frontend Extensions safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Comfyui Frontend Extensions use?

Comfyui Frontend Extensions is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Comfyui Frontend Extensions use?

About 5.4k tokens (SKILL.md is roughly 21k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.9k tokens, read only when the agent opens those files.

What are the alternatives to Comfyui Frontend Extensions?

Skills that share tags, products or a category with Comfyui Frontend Extensions: Comfyui Skill Openclaw (HuangYuChuh/ComfyUI_Skills_OpenClaw, 413 stars), ComfyUI Custom Node Builder (ConstantineB6/comfy-pilot, 230 stars), Continuity Render (roadmaus/ComfyUI-Continuity, 133 stars) and Add Comfyui Node (Mooshieblob1/MooshieUI, 207 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Comfyui Frontend Extensions?

artokun (a GitHub user) maintains it in artokun/comfyui-mcp, which has 803 GitHub stars. The repository holds 42 skills in this directory. The repository was last updated on October 5, 2026.

Source: artokun/comfyui-mcp on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.